There are several processing machines that use disks having a plurality of radially extending teeth on the surface of the disk, see FIG. 2, to reduce the size of particles. In general, the equipment uses two disks, with the surface having the teeth facing one another, spaced apart, so the teeth do not touch. The material to be reduced in size is fed between the disks as at least one disk rotates relative to the other. Such equipment may include, for example, pulverizers and powder mills. This equipment may be used to reduce the size on any material, such as, but not limited to, flour, wood, plastic resin, and recycled plastic.
During operation, the teeth become dull. With dulling, the efficiency of the equipment's size reduction capacity is diminished. Accordingly, the teeth are periodically sharpened. To date, the teeth sharpening process has been a ‘grinding’ process. Grinding, as used in the machining arts, refers to an operation using an abrasive wheel. In the grinding process, sharpening is performed by a grinding wheel (typically made with either diamond or poly cubic boron nitride (PCBN)) in a ‘wet’ process. In the wet process, the coolant, for example, oil (for diamond wheels) or synthetic or semi-synthetic oil (for PCBN wheels), is used to cool the grinding wheel and the teeth, and to remove swarf scraped from the teeth by the grinding wheel. These grinding wheels are expense (costing between $1800-3000) and the grinding machine is expensive (typically about $500,000) too. This process is also time-consuming (typically, depending on the extent of wear, from 2-4 hours per disk). Grinding typically requires 2-4 passes of the grinding wheel per tooth to completely sharpen the tooth and the speed of grinding is typically about 12 inches/minute. All of the foregoing makes the typical cost to sharpen the teeth on a disk, by grinding, about 10% of the cost of a new disk each time it is processed, and the lead time for sharpening can be great.
Accordingly, there is a need for new method to sharpen the radial teeth on the surface of a disk.